iOS 9.1, iOS 9.2, and More
Finally, you can count on Apple to take an approach similar to the one it took with iOS 8.
This year's iOS release was a little different than most in that the company released an abnormal amount of big upgrades. Sure, we saw the usual bug fixes (iOS 8.1.3, etc) but we also saw the company release iOS 8.3 and iOS 8.2 on top of iOS 8.1. The company is also planning an iOS 8.4 release.
Apple hasn't outlined its strategy but we wouldn't be surprised if it follows a similar release pattern with iOS 9. By releasing multiple updates, Apple can drum up excitement throughout the year, add features at a reasonable pace, and take advantage of a deep beta program.
We'd expect Apple to release iOS 9.1 and iOS 9.2, at the very least.